Aberrant expression of the extracellular matrix component Biglycan regulated by Hedgehog signalling promotes colorectal cancer cell proliferation.

Hedgehog (Hh) signalling plays essential roles in regulating embryonic development and contributes to tumour initiation, growth and progression in multiple cancers. The detailed mechanism by which Hh signalling participates in tumour growth warrants thorough study, although several downstream target genes have been identified. Herein, a set of novel targets of Hh signalling was identified in multiple types of tumour cells via RNA-Seq analysis. Among these targets, the expression regulation and oncogenic function of the extracellular matrix component biglycan (BGN) were investigated. Further investigation verified that Hh signalling activates the expression of BGN via the transcription factor Gli2, which directly binds to the promoter region of BGN. Functional assays revealed that BGN facilitates tumour cell growth and proliferation in colorectal cancer (CRC) cells, and xenograft assays confirmed that BGN also promotes tumour growth . Moreover, analysis of clinical CRC samples showed that both the protein and mRNA levels of BGN are increased in CRC tissues compared to those in adjacent tissues, and higher expression of BGN is correlated with poorer prognosis of CRC patients, further confirming the function of BGN in CRC. Taken together, aberrantly activated Hh signalling increases the expression of BGN, possibly regulates the extracellular matrix, and thereby promotes tumour growth in CRC.

Positive feedback of SuFu negating protein 1 on Hedgehog signaling promotes colorectal tumor growth.

Hedgehog (Hh) signaling plays a critical role in embryogenesis and tissue homeostasis, and its deregulation has been associated with tumor growth. The tumor suppressor SuFu inhibits Hh signaling by preventing the nuclear translocation of Gli and suppressing cell proliferation. Regulation of SuFu activity and stability is key to controlling Hh signaling. Here, we unveil SuFu Negating Protein 1 (SNEP1) as a novel Hh target, that enhances the ubiquitination and proteasomal degradation of SuFu and thus promotes Hh signaling. We further show that the E3 ubiquitin ligase LNX1 plays a critical role in the SNEP1-mediated degradation of SuFu. Accordingly, SNEP1 promotes colorectal cancer (CRC) cell proliferation and tumor growth. High levels of SNEP1 are detected in CRC tissues and are well correlated with poor prognosis in CRC patients. Moreover, SNEP1 overexpression reduces sensitivity to anti-Hh inhibitor in CRC cells. Altogether, our findings demonstrate that SNEP1 acts as a novel feedback regulator of Hh signaling by destabilizing SuFu and promoting tumor growth and anti-Hh resistance.

Construction and validation of a 6-gene nomogram discriminating lung metastasis risk of breast cancer patients.

Breast cancer is the most common malignant disease in women. Metastasis is the foremost cause of death. Breast tumor cells have a proclivity to metastasize to specific organs. The lung is one of the most common sites of breast cancer metastasis. Therefore, we aimed to build a useful and convenient prediction tool based on several genes that may affect lung metastasis-free survival (LMFS). We preliminarily identified 319 genes associated with lung metastasis in the training set GSE5327 (n = 58). Enrichment analysis of GO functions and KEGG pathways was conducted based on these genes. The best genes for modeling were selected using a robust likelihood-based survival modeling approach: GOLGB1, TMEM158, CXCL8, MCM5, HIF1AN, and TSPAN31. A prognostic nomogram for predicting lung metastasis in breast cancer was developed based on these six genes. The effectiveness of the nomogram was evaluated in the training set GSE5327 and the validation set GSE2603. Both the internal validation and the external validation manifested the effectiveness of our 6-gene prognostic nomogram in predicting the lung metastasis risk of breast cancer patients. On the other hand, in the validation set GSE2603, we found that neither the six genes in the nomogram nor the risk predicted by the nomogram were associated with bone metastasis of breast cancer, preliminarily suggesting that these genes and nomogram were specifically associated with lung metastasis of breast cancer. What's more, five genes in the nomogram were significantly differentially expressed between breast cancer and normal breast tissues in the TIMER database. In conclusion, we constructed a new and convenient prediction model based on 6 genes that showed practical value in predicting the lung metastasis risk for clinical breast cancer patients. In addition, some of these genes could be treated as potential metastasis biomarkers for antimetastatic therapy in breast cancer. The evolution of this nomogram will provide a good reference for the prediction of tumor metastasis to other specific organs.

Combination of keratins and alpha-smooth muscle actin distinguishes secretory coils from ducts of eccrine sweat glands.

Eccrine sweat glands are comprised of secretory coils and ducts, which are distinct in morphology and function. To better understand the roles of the two parts in development, homeostasis, wound repair and regeneration of eccrine sweat glands, we must distinguish between them. In this study, the localization of keratins and alpha-SMA in human eccrine sweat glands was examined by immunofluorescence staining. Based on the differential localization of keratins and alpha-SMA in different cell types, four pairs of antibodies (K5/K7, K5/alpha-SMA, K14/K7 and K14/alpha-SMA) were used to differentiate secretory coils from ducts by double-immunofluorescence staining. Immunofluorescence staining showed that myoepithelial cells of secretory coils expressed K5, K14 and alpha-SMA, whereas secretory cells of secretory coils expressed K7, K8, K15, K18 and K19. Ductal cells expressed K5, K8, K14 and K19. Double-staining showed that the secretory coils were K5(+)/K7(+), K5(+)/alpha-SMA(+), K14(+)/K7(+) and K14(+)/alpha-SMA(+), whereas ducts were K5(+)/K7(-), K5(+)/alpha-SMA(-), K14(+)/K7(-) and K14(+)/alpha-SMA(-). In conclusion, by combining use of keratins and alpha-SMA antibodies, secretory coils can be easily differentiated from ducts in morphology.

Matrigel basement membrane matrix induces eccrine sweat gland cells to reconstitute sweat gland-like structures in nude mice.

BACKGROUND: Severe burn results in irreversible damage to eccrine sweat glands, for which no effective treatment is available. Interaction between the extracellular matrix and epithelial cells is critical for proper three-dimensional organization and function of the epithelium. METHODS: Matrigel-embedded eccrine sweat gland cells were subcutaneously implanted into the inguinal regions of nude mice. Two weeks later, the Matrigel plugs were removed and evaluated for series of detection items. RESULTS: Sweat gland cells developed into sweat gland-like structures in the Matrigel plugs based on: (1) de novo formation of tubular-like structures with one or more hollow lumens, (2) expression of epithelial and sweat gland markers (pancytokeratin, CK5/7/14/19, α-SMA and CEA), (3) basement membrane formation, (4) myoepithelial cells presenting in and encompassing the tubular-like structures, (5) cellular polarization, evident by the expression of tight junction proteins (claudin-1 and ZO-2), anchoring junctions (desmoglein-1 and -2 and E-cadherin) and CEA in the luminal membrane, (6) expression of proteins related to sweat secretion and absorption (Na(+)-K(+)-ATPase α/ß, Na(+)-K(+)-2Cl-cotranspoter 1, Na(+)/H(+) exchanger 1, aquaporin-5, epithelial sodium channel, cystic fibrosis transmembrane conductance regulator, potassium channel and vacuolar-type H+-ATPase), and (7) about 20% of the tubular-like structures are de novo coils and 80% are de novo ducts. CONCLUSIONS: This study provides not only an excellent model to study eccrine sweat gland development, cytodifferentiation and reconstitution, but also an in vivo model for regeneration of eccrine sweat glands.

Long-term tracing of the BrdU label-retaining cells in adult rat brain.

Stem cells have been shown to be label-retaining, slow-cycling cells. In the adult mammalian central nervous system, the distribution of the stem cells is inconsistent among previous studies. The purpose of the present study was to determine the distribution of BrdU-LRCs and the cell types of the BrdU-LRCs in rat brain. To label BrdU-LRCs in rat brain, six newborn rats were administered intraperitoneal injections of BrdU 50mg/kg/time twice a day at 2h intervals, over four consecutive days. The BrdU-LRCs were detected by immunohistochemistry, the cell types were examined by double immunofluorescence staining for BrdU/GFAP and BrdU/MAP2, and the percentage of BrdU-LRCs was calculated following a chase period of 24 weeks post-injection. We observed that BrdU-LRCs distributed extensively in rat brain. In the LV, DG, striatum, cerebellum and neocortex, the percentage of BrdU-LRCs was 11.3 ± 2.5%, 10.9 ± 1.3%, 6.4 ± 1.2%, 5.6 ± 0.8%, and 4.9 ± 0.6%, respectively. The highest density of BrdU-LRCs was in LV and DG, the known stem cell sites in adult mammalian brain. Both BrdU/GFAP and BrdU/MAP2 double-staining cells could be detected in the above five brain subregions. Ongoing cell production was widespread in the adult mammalian brain, which would allow us to reevaluate the capacity and potentiality of the brain in homeostasis, wound repair, and regeneration.

Localization of Na(+)-K(+)-ATPase α/ß, Na(+)-K(+)-2Cl-cotransporter 1 and aquaporin-5 in human eccrine sweat glands.

In order to evaluate the function of the repaired or regenerated eccrine sweat glands, we must first localize the proteins involved in sweat secretion and absorption in normal human eccrine sweat glands. In our studies, the cellular localization of Na(+)-K(+)-ATPase α/ß, Na(+)-K(+)-2Cl-cotransporter 1 (NKCC1) and aquaporin-5 (AQP5) in eccrine sweat glands were detected by immunoperoxidase labeling. The results showed that Na(+)-K(+)-ATPase α was immunolocalized in the cell membrane of the basal layer and suprabasal layer cells of the epidermis, the basolateral membrane of the secretory coils, and the cell membrane of the outer cells and the basolateral membrane of the luminal cells of the ducts. The localization of Na(+)-K(+)-ATPase ß in the secretory coils was the same as Na(+)-K(+)-ATPase α, but Na(+)-K(+)-ATPase ß labeling was absent in the straight ducts and epidermis. NKCC1 labeling was seen only in the basolateral membrane of the secretory coils. AQP5 was strongly localized in the apical membrane and weakly localized in the cytoplasm of secretory epithelial cells. The different distribution of these proteins in eccrine sweat glands was related to their functions in sweat secretion and absorption.

The cellular localization of Na(+)/H(+) exchanger 1, cystic fibrosis transmembrane conductance regulator, potassium channel, epithelial sodium channel γ and vacuolar-type H+-ATPase in human eccrine sweat glands.

The secretory portions of human eccrine sweat glands secrete isotonic fluid into the lumen and then the primary fluid is rendered hypotonic during its passage to the skin surface. During the processes of sweat secretion and absorption, many enzymes and proteins play important roles. In the study, the cellular localizations of Na(+)/H(+) exchanger 1 (NHE1), cystic fibrosis transmembrane conductance regulator (CFTR), potassium channel (KC), epithelial sodium channel γ (γENaC) and vacuolar-type H+-ATPase (V-ATPase) in human eccrine sweat glands and epidermis were detected using immunofluorescence labeling. The results revealed that in the secretory coils, the basolateral membranes showed evidence of CFTR, NHE1 and KC activities, the apical membranes showed the activities of KC and NHE1, and the nucleus showed γEaNC and V-ATPase activities; in the duct, the peripheral and luminal ductal cells showed evidence of CFTR, NHE1 and KC, the apical membranes showed the activities of CFTR and NHE1, and the nucleus showed γEaNC, V-ATPase and KC activities. The cellular localization of these proteins in eccrine sweat glands is helpful to better understand the mechanisms of sweat secretion and absorption.